Does chronic opioid use really reduce pain?

The articles by Kahan and colleagues on opioids for managing chronic non-malignant pain¹ and misuse of and dependence on opioids² in the September issue of Canadian Family Physician contained much useful information. They did not, however, address the problem of developing tolerance. I have seen many patients who have developed such tolerance and have been struck by the fact that, if they have an injury or even undergo venipuncture, they seem to have as much pain as other people who are not taking narcotics. I wonder whether chronic opioid use really does reduce pain.